Mesen2/UI/App.axaml.cs

using Avalonia;
using Avalonia.Controls;
using Avalonia.Controls.ApplicationLifetimes;
using Avalonia.Controls.Platform;
using Avalonia.Markup.Xaml;
using Avalonia.Styling;
using Avalonia.Threading;
using Mesen.Config;
using Mesen.Interop;
using Mesen.Localization;
using Mesen.Utilities;
using Mesen.ViewModels;
using Mesen.Windows;
using System.IO;
using System.Reflection;

namespace Mesen
{
	public class App : Application
	{
		public static bool ShowConfigWindow { get; set; }

		public override void Initialize()
		{
			if(Design.IsDesignMode || ShowConfigWindow) {
				RequestedThemeVariant = ThemeVariant.Light;
			} else {
				RequestedThemeVariant = ConfigManager.Config.Preferences.Theme == MesenTheme.Dark ? ThemeVariant.Dark : ThemeVariant.Light;
			}
			
			Dispatcher.UIThread.UnhandledException += (s, e) => {
				MesenMsgBox.ShowException(e.Exception);
				e.Handled = true;
			};

			AvaloniaXamlLoader.Load(this);
			ResourceHelper.LoadResources();
		}

		public override void OnFrameworkInitializationCompleted()
		{
			if(ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop) {
				if(ShowConfigWindow) {
					new PreferencesConfig().InitializeFontDefaults();
					desktop.MainWindow = new SetupWizardWindow();
				} else {
					try {
						desktop.MainWindow = new MainWindow();
					} catch {
						//Something broke when trying to load the main window, the settings file might be invalid/broken, try to reset them
						Configuration.BackupSettings(ConfigManager.ConfigFile);
						ConfigManager.ResetSettings(false);
						desktop.MainWindow = new MainWindow();
					}
				}
			}
			base.OnFrameworkInitializationCompleted();
		}
	}
}